Synthesis of Piano Stool Complexes Employing the Pentafluorophenyl Substituted Diphosphine (C6F5)2PCH2P(C6F5)2 and the Effect of Phosphine Modifiers on Hydrogen Transfer Catalysis.

Ruthenium, rhodium, and iridium piano stool complexes of the pentafluorophenyl-substituted diphosphine (C6F5)2PCH2P(C6F5)2 (2) have been prepared and structurally characterized by single-crystal X-ray diffraction. The Cp-P tethered complex [{(C5Me4CH2C6F4(C6F5)CH2P(C6F5)2}RhCl2] (9), in which only one phosphorus is coordinated to the rhodium, was prepared by thermolysis of a slurry of [Cp*RhCl(-Cl)]2 and 2 and was structurally characterized by single-crystal X-ray diffraction. The tethering occurs by intramolecular dehydrofluorinative coupling of the pentamethylcyclopentadienyl ligand and P,P-coordinated 2. The geometric changes that occur on tethering force dissociation of one of the phosphorus atoms. The effects of introducing phosphine ligands to the coordination sphere of piano stool hydrogen transfer catalysts have been studied. The complexes of fluorinated phosphine complexes are found to transfer hydrogen at rates that compare favorably with leading catalysts, particularly when the phosphine and cyclopentadienyl functionalities are tethered. The highly chelating Cp-PP complex [(C5Me4CH2-2-C5F3N-4-PPhCH2CH2PPh2)RhCl]BF4 (1) was found to outperform all other complexes tested. The mechanism of hydrogen transfer catalyzed by piano stool phosphine complexes is discussed with reference to the trends in activity observed.

Il Piano della Performance 2011-2013 dei Comuni italiani di medie e grandi dimensioni: allineamento normativo e adeguatezza programmatica in ottica economico-aziendale

Il presente lavoro intende individuare le possibili configurazioni di Piano della Performance (PdP) utilizzabili dagli enti locali, provvedendo poi a delineare il livello di distribuzione e di allineamento dei PdP 2011-2013 dei Comuni medi e grandi rispetto alle suddette configurazioni. Inoltre, verrà valutato, tramite una griglia predisposta dagli autori, il livello di adeguatezza programmatica dei Piani della Performance dei Comuni medi e grandi, al fine di confermare le configurazioni esistenti o di proporne una nuova in caso di inadeguatezza delle prime.